fix: make tool progress live-only - #38217

What

Make running tool progress a live replacement snapshot instead of durable session history, suppress unchanged shell snapshots, and preserve useful partial output when a tool fails.

The deterministic shell fixture (printf steady; sleep 3.4) improves from:

This proves deterministic work removal; it does not claim an exact CPU-time reduction.

Before / After

Before

1. Shell polled cumulative output every second and published the same snapshot even when output had not changed.
2. Every progress snapshot became a durable session.tool.progress.1 row and was projected, synchronized, and replayed.

After

1. Shell publishes only when its output or truncation state changes.
2. Running progress is ephemeral and replace-style; only called/success/failed remain durable.
3. Existing durable progress rows are deleted without changing aggregate sequence watermarks; sequence gaps remain valid.
4. The runner retains the latest progress snapshot in memory. If the tool fails, its durable failure includes non-empty partial content and progress metadata; both fields are omitted when no progress occurred.
5. Existing reducers temporarily project failure metadata into the current state.structured field, so replayed and reconnected failures retain useful partial state.

How

• packages/schema/src/session-event.ts makes SessionEvent.Tool.Progress ephemeral.
• packages/schema/src/session-event.ts gives failures optional non-empty content and optional progress metadata without changing the terminal error outcome.
• packages/core/src/session/runner/publish-llm-event.ts retains the latest snapshot in memory and attaches it to each failure path when present.
• packages/core/src/tool/shell.ts suppresses exact duplicate { output, truncated } snapshots.
• Core, CLI, ACP, TUI, noninteractive, and mini-stream reducers project terminal failure snapshots while retaining their live-state fallback.
• packages/core/src/database/migration/20260722011141_delete_tool_progress_events.ts deletes obsolete session.tool.progress.1 rows and deliberately leaves event_sequence unchanged.
• packages/client/src/promise/generated/types.ts is regenerated from the current protocol.

Scope

• Does not add process-global subscription interest scoping; that larger fan-out optimization remains separate.
• Does not add cursor-based shell reads; shell still polls cumulative output from offset zero.
• Does not periodically re-emit unchanged running progress after reconnect.
• Does not introduce a larger settlement union, remove result, rename projected state, or redesign void output.
• Accepts removal of obsolete progress payloads from raw historical event reconstruction. Existing projections are not deleted.
• Does not include the repository-wide stale OpenAPI snapshot refresh or legacy combined SDK regeneration; those produce unrelated baseline churn on the V2-only branch.

Testing

• cd packages/core && bun test test/database-migration.test.ts test/session-runner-tool-events.test.ts test/session-runner.test.ts test/session-tool-progress.test.ts test/tool-shell.test.ts --only-failures (passed)
• cd packages/tui && bun test test/mini/stream-v2.transport.test.ts test/cli/tui/data.test.tsx --only-failures (87 passed)
• cd packages/cli && bun test test/acp/event-behavior.test.ts test/run/noninteractive.test.ts --only-failures (18 passed)
• cd packages/client && bun run test (43 passed)
• cd packages/schema && bun test test/event-manifest.test.ts --only-failures (6 passed)
• cd packages/core && bun run script/migration.ts --check (passed)
• Push hook bun turbo typecheck --concurrency=3 passed in all 33 applicable packages.
• git diff --check passed.
• bun run lint exits nonzero on repository-wide baseline warnings; no changed production file introduced a lint diagnostic.

Flow

sequenceDiagram
  participant Tool
  participant Runner
  participant Live as Live subscribers
  participant Log as Durable event log

  Tool->>Runner: progress(snapshot)
  Runner->>Runner: retain latest snapshot
  Runner-->>Live: session.tool.progress
  Note over Live,Log: progress is not persisted
  Tool->>Runner: failure
  Runner->>Log: durable error + optional partial snapshot
  Log-->>Live: replayable failure